The liquid-crystalline smectic blue phases

TL;DR

This paper introduces smectic blue phases, a new type of liquid crystal mesophase characterized by unique geometrical frustrations and broken cubic symmetry, expanding understanding of liquid crystal phases.

Contribution

It reports the discovery and characterization of smectic blue phases, revealing their unique symmetry properties and the coexistence of smectic order with blue phase features.

Findings

Smectic blue phases exhibit double geometrical frustration.

They have quasi-long range smectic order.

Symmetry analysis shows broken cubic symmetry.

Abstract

Smectic blue phases (BPSm) are new mesophases of thermotropic liquid crystals, which exhibit a double geometrical frustration: the extension of chirality in three spatial dimensions like the classical blue phases, and helical twist competing with smectic order, as in the TGB phases. The existence of a quasi-long range smectic order in BPSm phases breaks the cubic symmetry of classical blue phases. The symmetries of these new phases have been determined by X-ray scattering and optical polarizing microscopy experiments.